Dry Dredgers Field Trip
May 24, 2008
Harsha/East Fork Lake, Ohio

It was a perfect May day for the Dry Dredgers field trip to Harsha/East Fork Lake. This is a continuation of our 2008 field trip series to fossil sites we have not visited in a while. Our last visit was in 1999

At Harsha/East Fork Lake, fossil collecting is permitted only in the spillway and then only with permission. Persons wishing to collect fossils sign in at the visitor center located near the dam. So that is where we met that day before proceeding to the site.
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Once everyone was there, we proceeded to the spillway. This spillway is an extremely large flat area that exposes the Fairview Formation.

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This site was chosen for May as a good site for families. And as anticipated, young and old alike turned out to find that elusive trilobite and quantities of common gastropods.

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Fossils Found That Day


Quite a few crinoid fossils were found. This first one is a crinoid arm with pinnules on the surface of a rock.

Then someone found a calyx (head) of Ectenocrinus simplex (next 2 pics)
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Among the crinoid holdfasts found what this interesting specimen where a crinoid stem is wrapped around a Bryozoan

Also found were individual plates from a crinoid calyx.

Most fragments of crinoids, though, were stems, some articulated on a rock surface like the one below.


Being a good exposure of the Fairview Formation, a few examples of an interesting Bryozoan that is mostly limited to the Fairview Formation were found, Escharopora falciformis. These spear-shaped bryos have monticules (holes) that are diamond shaped. 

Another interesting bryozoan was a ramose (branching) variety with stellate (star shaped) monticules, Constellaria florida.

These ramose bryozoans can be found in large colonies, the gaps of which have been filled in with rock matrix. 


On this site there are layers in which you can find a very collectable brachiopod that is somewhat limited to the Fairview formation, Plectorthis fissicosta.(next 2 pics).

Not sure about this one. It looks more like a Glyptorthis, but it's from the Fairview formation. It could be a Plectorthis, but the hinge is not flat enough. Any thoughts from the viewers?

More common are the plentiful brachiopod, Vinlandostrophia (several species: next 2 pics).  Most were P. hopensis.

A few nice Trematis millepunctata were found. These are inarticulate brachipods that have a white residue that shows some of the tiny holes that made up the surface of this brach.

Most of the Hebertella we found were broken and on rock surfaces.

The site was not without Vinlandostrophia ponderosa. But they were not as common as what we are used to in the Bellevue Formation which was not exposed here except for on the hill tops above the spillway where collecting is not permitted.


Not much in the way of Flexicalymene trilobites were found. But this site was great for plenty of large fragments of the trilobite Isotelus. The first 3 pictures show some of the Hypostomes (mouth plates) that were found. 

Here's a nice fragment of the thorax, showing some of the 8 segments Isotelus have.

Other fragments were from the genal area (next 4 pics).
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This site was great for large quantities of gastropods. The most common was Paupospira. (next 3 pics)

The next common Gastropod found was Cyclonema.

Internal molds of gastropods abounded. Even cross sections of rocks showed the interesting patterns created by these snail shells, partially replaced by calcite crystals.

Most internal molds were free from the rock matrix and all over the ground.


Not many specimens of the often plentiful straight-shelled nautiloid cephalopod were found. Here's one though.

Trace Fossils

As is true for most Fairview Formation sites, we found examples of trace fossils on the surface of rocks. There is a particularly strange variety that keeps popping up on the sites we visit. The example shown below has straight, 3-sided and 4-sided burrows that taper to a point. It is a very distinct shape. The burrows are randomly distributed. 
See Photos of this same trace at another site in 2005

Pelecypods (clams)

A few internal molds of clams were found. (Hey, is that a tail section of an Isotelus trilobite??!! I've got to look closer at what members find when I'm taking the pictures. I often draw a different conclusion when looking at the photos later.)


And finally, a more recent fossil found on the lake spillway floor. Similar to trilobites, this crayfish is a molt, not a dead animal. Crustaceans shed their exoskeletons periodically, leaving molts that look like the complete animal. Check your trilobite fossils, folks. They could be just one of many molts the animal shed in it's lifetime.

That's it for this field trip. Hope you enjoyed it as much as we did out there.

Next field trip: June 2008: Penn Dixie Site, NY

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